voxelize VTU file in python

Question

How can I voxilize the attached vtk unstractured file (VTU) using python? Ideally I want to define the region (xmin=-9, xmax=9) and (ymin=-9, ymax=9) and the number of pixels (e.g (256,256) in each direction) and extract that region onto the pixel grid and store in file (with hollow regions filled).

VTUfile

here is how I read the file into polyData

import vtk

# Read the source file.
reader = vtk.vtkXMLUnstructuredGridReader()
reader.SetFileName("internal.vtu")
reader.Update()  
polydata = reader.GetOutput()

How can I convert the polydata now into the file with above details?

Thanks

Answer 1

Not sure if this helps, I had a similar problem using vtkplotter recently which might turn useful to you:

from vtkplotter import *
import numpy as np

g = load('internal.vtu')
g.pointColors("p", cmap='terrain')

pts = g.points()
field = g.getPointArray('U')
ars = Arrows(pts-field/5, pts+field/5, c='k')

zpr = np.linspace(-15,15, num=25)
probes = np.c_[np.zeros_like(zpr)-10, np.zeros_like(zpr), zpr]

str_lns = streamLines(g, probes, activeVectors='U', maxPropagation=60, lw=2)
str_lns.pointColors(cmap='jet')
str_lns.GetProperty().LightingOff()
str_lns.mapper().SetResolveCoincidentTopologyToPolygonOffset()

show(g, ars, Points(probes), str_lns, elevation=90)

vol = interpolateToVolume(g, dims=(50,2,50), bounds=(-9,9,0,0,-9,9))
# vol.imagedata() # retrieves the vtkImageData obj
lego = vol.legosurface(cmap='terrain')

show(lego, newPlotter=True, elevation=90)